Stages of development1- Stage of processes: Five processes appear around the

stomodium:(one frontonasal +two maxillary + two mandibular).

2- Stage of meeting. 3- Stage of fusion.

Structures contributing to the formation of the face

Process Structures Formed

Frontonasal Forehead- tip, dorsum and ala of nose- upper eye lids- philtrum of the upper lip.

Maxillary Lower lids- upper part of the cheeks- lateral part of the upper lip- upper jaw.

Mandibular Lower lip- chin- lower part of the cheeks- lower jaw.

Correlation between sensory nerve supply of the face and its development

The process and its derivatives

Nerve supply

Frontonasal Ophthalmic nerve

Maxillary Maxillary nerve

Mandibular Mandibular nerve

Congenital anomalies:1-Cleft upper lip ( hare lip): Due to failure of fusion between maxillary

and intermaxillary processes (philtrum and lateral part of upper lip).

2-Oblique facial cleft: Due to failure of fusion between maxillary

process and lateral and medial nasal processes.

3-Median cleft lower lip: Due to failure of fusion between the

mandibular processes.

4-Macrostomia (larg mouth): Due to arrest of fusion between the maxillary

and mandibular processes to shift the angle medially >>> very big oral fissure.

5-Microstomia: Due to excessive fusion between the

maxillary and mandibular processes >>>>very small oral fissure.

SStage of processes Stage of meeting

Stage of fusion

Stages of development1- Stage of processes: (primitive or primary palate + two palatine

processes giving secondary palate). 2- Stage of meeting. 3- Stage of fusion. Intermaxillary process 1ry palate

premaxilla of hard palateIncisive fossa.Maxillary processes palatine processes

2ry palate meeting& fusion with 1ry palate.

The anterior ¾ of the palate ossify hard palate & posterior ¼ the soft palate.

Congenital anomalies1- Cleft palate: a- Bifid uvula. b- Cleft soft palate. c- Cleft soft and hard

palate.Due to failure of fusion

between the processes.2- Perforated palate: due to failure of fusion

between the two palatine processes at certain points.

Development of tongue

Development of tongue1- The anterior two thirds: Origin: The 1st Pharyngeal arch (mandibular

processes) two lateral lingual processes+ one tuberculum impar meet fuse anterior 2/3 of the tongue U shaped sulcus mobile tongue leaving frenulum linguae.

2- The pharyngeal part (posterior third): Origin: 2nd and 3rd pharyngeal arches four swellings

meet fuse copula of His posterior third of the tongue.

N.B.: 1- The site of fusion between the lateral lingual swelling is indicated by the median sulcus.

2- The site of fusin between anterior 2/3 & posterior 1/3 is indicated by Y- staped sulcus terminalis.

Muscles of the tongueThree or four occipital

myotomes migrate to enter the tongue forming muscles of the tongue.

The occipital myotomes are supplied by the hypoglossal nerve which migrate with them to supply the tongue muscles during their development.

Correlation between development of tongue and its nerve supply

Anterior 2/3 develop from the first arch supplied by mandibular nerve and chorda tympani (nerves of 1st arch).

Posterior 1/3 develops from the second and third arches but it is supplied by the glossopharyngeal nerve and internal laryngeal nerves( nerves of the third arch). This is because the element of the third arch grows superficially over the element of the second arch and hid it.

Occipital myotomes are supplied by hypoglossal nerve which migrates with them to supply the tongue muscles.

Congenital anomalies1- Bifid tongue: Due to incomplete fusion

between the two lateral lingual swellings.2- Trifid tongue: The tuberculum impar

elongates& separates the lateral swellings three parts.

3- Tie tongue ( ankyloglossia): due to attachment of frenulum linguae to the tip of the tongue interfere with protrusion and speech.

4- Macroglossia: large tongue.5- Microglossia: small tongue.6- Hemiglossia: Non development of one lateral

swelling.7- Aglossia: no tongue.

Prof.: Dr. Wafaa Abdel-Rahman